Joachim Erdei, Michal Joachimczak and Borys Wróbel

Abstract

Co-evolution of predators and prey is an example of an
evolutionary arms race, leading in nature to selective pressures
in positive feedback. We introduce here an artificial
life ecosystem in which such positive feedback can emerge.
This ecosystem consists of a 2-dimensional liquid environment
and animats controlled by evolving artificial gene regulatory
networks encoded in linear genomes. The genes in
the genome encode chemical products which regulate other
genes, sense the environment (the scent of food, prey and
predators), control the animat's movement, and its foraging
strategy. An animat can switch multiple times in its
life between two foraging strategies (with different metabolic
costs): a predator can derive food from the prey, prey just
from food that diffuses in the environment. When an animat
consumes enough food (or prey), it produces an offspring
with a mutated genome. Mutations introduce variation into
the population, and this diversity together with selective pressures
leads to the evolution of control for diverse foraging
strategies in an ecosystem that can support hundreds of individuals.